The present invention pertains generally to devices and methods for performing angioplasty or stent emplacement procedures. More particularly, the present invention pertains to angioplasty balloon catheters that incorporate cutting blades on the surface of the balloon. The present invention is particularly but not exclusively useful as a device and method which incorporates a cutting blade that will anchor the balloon to the stenosis during an angioplasty procedure or the emplacement of a stent in the vasculature of a patient.
Angioplasty and stent emplacement procedures have been successfully used for many years for the treatment of vasculature diseases. Typically, in an angioplasty procedure, an inflatable balloon is inserted on a catheter into the vasculature and is positioned in a vessel of the vasculature at the site of a stenosis. The balloon is then inflated to dilate the stenosis for improved blood flow through the vessel. Inflatable balloons are also widely used for procedures wherein a stent is to be positioned into the vasculature of a patient.
In recent years a significantly important advancement has been made in angioplasty procedures with the introduction of the so-called xe2x80x9ccutting balloon.xe2x80x9d More specifically, such a xe2x80x9ccutting balloonxe2x80x9d incorporates blades which are mounted on the surface of the balloon to cut into a stenosis as the balloon is inflated to dilate the stenosis. For example, such a xe2x80x9ccutting balloonxe2x80x9d is disclosed and claimed in U.S. Pat. No. 5,797,935 which issued to Barath for an invention entitled xe2x80x9cBalloon Activated Force Concentrators for Incising Stenotic Segmentsxe2x80x9d and which is assigned to the same assignee as the present invention. It happens, however, that despite such significant technical advances, the very nature of a particular stenosis can pose additional concerns for consideration.
As is well known, a stenosis in a vessel of the vasculature can be one of many different types and can have various configurations. For instance, some are of a rather slippery consistency. Additionally they may have a configuration that makes it particularly difficult to maintain the position of an angioplasty balloon at the site of the stenosis as the balloon is being inflated. Specifically, it can happen that as the balloon is being inflated, the forces that are generated between the balloon and the stenosis can cause the balloon to be displaced from the site of the stenosis. Obviously, this so-called xe2x80x9cwatermelon seedxe2x80x9d reaction can be disruptive of an angioplasty procedure.
The above-noted problems are also present, and can be particularly troublesome, in procedures wherein a stent is to be emplaced at a site in the vasculature. As mentioned above, such sites may involve a slippery stenosis that can adversely effect efforts to properly position the stent.
In light of the above, it is an object of the present invention to provide a system and method for anchoring the inflatable balloon of a balloon catheter to a stenosis in the vasculature of a patient during an angioplasty or stent emplacement procedure. Another object of the present invention is to provide an improved xe2x80x9ccutting balloonxe2x80x9d catheter which incorporates specifically configured blades that will prevent both axial (translational) and azimuthal (rotational) movements of the balloon relative to the vessel (stenosis site) during an angioplasty procedure. Still another object of the present invention is to provide a system and method for anchoring the balloon of an angioplasty balloon catheter to a stenosis in the vasculature of a patient that is relatively simple to manufacture, is easy to implement, and is comparatively cost effective.
A system and method for anchoring an angioplasty catheter to a stenosis in the vasculature of a patient requires an elongated inflatable balloon and specially configured blades mounted on the surface of the balloon. More specifically, the balloon defines a longitudinal axis and is mounted on a catheter for selective movement between a deflated configuration and an inflated configuration. In the deflated configuration the surface of the balloon is effectively collapsed onto the axis. In the inflated configuration, however, the surface of the balloon is radially distanced from the axis.
For the present invention, at least one elongated blade (main-blade) is mounted on the surface of the balloon. Preferably, the main-blade is axially oriented substantially parallel to the axis that is defined by the balloon. Additionally, there is at least one grip that is conformed with the blade. More specifically, the grip is azimuthally oriented on the axis that is defined by the balloon, and it protrudes in a substantially radial direction from the axis of the balloon.
For one embodiment of the present invention the grip is a serration(s) that is formed into the cutting edge of the main-blade. In another embodiment the grip is a cross-blade that forms an angle xcex1 with the blade. In accordance with the present invention this angle xcex1 can be ninety degrees, or it may be greater or less than ninety degrees depending on the particular needs of the user. Further, as contemplated for the present invention, the blade and the grip can be made of stainless steel.
For an alternate embodiment of the present invention the system can include a stent that is to be emplaced in the vasculature of the patient. Specifically, as is well known, the stent is positioned on the balloon for movement with the balloon as the balloon is inflated from its deflated configuration and into its inflated configuration. Thus, the stent can be expanded for emplacement in the vasculature of the patient. Further, when a stent is included in the system of the present invention there can be a plurality of anchoring blades mounted on the balloon. In this case, preferably, each blade is axially aligned with at least one other blade, with a distance therebetween. The stent can then be positioned on the balloon between the blades.
In operation, as the balloon is inflated into its inflated configuration, the blade and its conformed grip are embedded into the stenosis. This effectively anchors the balloon to the stenosis as the axially oriented main-blade prevents azimuthal (rotational) movement in the vessel relative to said stenosis. At the same time the azimuthally oriented grip prevents axial (translational) movement of the balloon in the vessel relative to the stenosis.
It is within the contemplation of the present invention that the system will include a plurality of main-blades. Furthermore, it is contemplated that each of the plurality of main-blades may have a plurality of conformed grips. Additionally, some of the plurality of main-blades can be axially aligned with each other. Also, each main-blade can be azimuthally distanced from at least one other main-blade by an angle xcex2. Thus, a series of main-blades can be present in different azimuthal locations on the surface of the balloon.